Russell Brand and Jonathan Ross: the BBC Trust said it was 'dismayed' at the presenters' on-air comments. Photograph: BBC

The BBC Trust has ordered the corporation's management to broadcast a Radio 2 apology to licence fee payers over the prank calls made by Jonathan Ross and Russell Brand to Andrew Sachs and said it was "dismayed" at the "offensive comments" they made on-air.

In a strongly worded statement by BBC Trust standards, the corporation's regulatory and governance body described the "Sachsgate" broadcast by Brand and Ross on Radio 2 on Saturday October 18 as a "serious and deliberate breach of BBC editorial guidelines on offence and privacy".

A statement from the BBC Trust said: "The BBC Trust represents licence fee payers and on their behalf has a responsibility to safeguard high standards of BBC broadcasts.

"The trust is dismayed both that the offensive comments broadcast on the Russell Brand Show on October 18 fell so far short of audiences' legitimate expectations, and by the deplorable intrusion in to the privacy of Mr Sachs and his granddaughter.

"The transmission of these comments via a BBC Radio programme represents an abuse of the privilege given to the BBC to broadcast to its audiences. On behalf of the BBC, the trust offers a full and unreserved apology to Andrew Sachs, Georgina Baillie and the rest of his family. The trust extends this apology to licence fee payers as a whole."

The statement went on: "The trust has required the executive to issue an on-air apology to licence fee payers on BBC Radio 2 for the serious and deliberate breaches of the BBC editorial guidelines on offence and privacy.

"The form and timing of the apology will be agreed by the trust's committee. We have also required the director general to write personally to Andrew Sachs and Georgina Baillie to apologise on behalf of the corporation.

However, the trust said "editorial control and compliance procedures in non news areas of the BBC's audio and music department are inadequate and need to be strengthened".

The trust has asked its editorial standards committee to "review these issues" at its meeting next week and requested a "final, written report from the director general at its next meeting on November 20 on all relevant issues".

The statement went on: "Furthermore, we have requested the executive to strengthen immediately the editorial controls around any programme which represents high levels of editorial risk.

"Also in this area, we have asked the executive to assess immediately the editorial controls and compliance procedures in place for all programmes – across television and radio – where the production company is owned and/or managed by the featured performer."

Brand's programme was made by his own production company, Vanity Projects.

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